End Mill Replacements

I managed to snap a end mill today. I was thinking I’d replace the collection as there isn’t much available in the shop.

What is recommended? I was going to go HSS over carbide but is there any preference / suggestion for manufacturer? Just looking at the prices on Amazon shows quite the range.

Were you using those gold ones from the mill drawer? Those are all junk, so I wouldn’t worry at all about replacing them. Plus that particular collection is rather absurd. End mills are not drill bits; there is rarely need for so many different sizes.

Right now, as I teach in the Mill class, end mills are basically consumables that you need to provide yourself, though you are welcome to use the few terrible ones we have available. We were considering changing this and offering more end mills at some point, but we haven’t gotten around to it.

What I was planning to get was just a few end mills, a two-flute and a four-flute for each size. Probably just 1/4", 3/8", and 1/2". Definitely only HSS for general use; carbides are too fragile for that. But I don’t know what brands to get. If you want to research that for me, that might be helpful, but don’t look on Amazon.

I am curious how you managed to snap one of those end mills; most of those that remained were rather large diameter. Breaking the end of a flute is not uncommon, but you really shouldn’t be doing anything that would snap an end mill with a 1/4" or greater diameter.

Thanks for the reply Ethan. Yes, I was using one of the gold ones from the drawer. I’m not too sure what I was doing incorrectly, I was milling the edge of a mild steel piece at speed L2. It was giving some resistance before the snap, something I will be more attentive to in the future. Should I further reduce speed? L2 had worked well for me in the past.

I’ll pick up my own HSS for future use.

What size was the end mill? L2 is likely one or two steps too low.

The brand I bought for my own use was Melin. They seem fine; I just haven’t researched all the options. @EricP, @JoeN, @fixinit: Do you have brand recommendations for end mills?

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I think it was the 1/4th, and I think I had been using a smaller end mill the last time I was using it. I couldn’t find it last night, though.

Four-flute I assume. I would definitely try H1 for that size bit on mild steel.

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This is my approach to end mills:

  1. I’m never buying Amazon tooling again. It consistently disappoints

  2. for an outside edge, use the largest diameter you have (or can afford). That will get your surface speed up. For me, this is a 1/2".

  3. I’m not particular to brands, but the best approach is to call a supplier and talk people who live and breathe tooling. Different material does better with different helix angles, number of flutes, etc. so it’s a rather complex topic. You can do this for free by calling Sparktech (512) 716 3131. Andrew or ___(I forget his name) will answer, recommend something they have in stock, then drive by and pick up two of them if it’s anything you are likely to break. I get all carbide, then run the mill at max RPM.

  4. if you need to plunge or pocket, make sure the end mill you buy is cross cut.

Note: SparkTech has a retail store and an eBay store. I’m usually buying out of the retail store because they have a huge selection and consult on the purchases. You can also sometimes find what you need listed on eBay under “driller1” but there you are on your own for tool selection. The Sparktech website isn’t very helpful.



If you live south. Check out Dixie Tool Crib. They rep only good endmills. It has been a while, but I purchased a 4 flute 3/8" endmill for $15. It is a way better deal than cheap unknown brands that will snap on you or are only good for roughing cuts.

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Dixie Tool Crib is where I got the Melin end mills. I was happy with them until they sold me some carbide end mills when I specifically asked for HSS; I didn’t check carefully because I was discussing a different tooling problem and trusted them. So just check that you are actually getting what you asked for.

So note that Alex recommends all carbide while I get all HSS. That’s partially because he does mostly steel and I do mostly aluminum, but I think it’s mainly a personal preference. In the long run, I’ll go through twice as many end mills that cost half as much each.

I’d also like to put an asterisk on “never buying Amazon tooling” – Shars has an Amazon store, and the fulfilled-by-Amazon delivered price is often better than buying from the Shars website and paying their shipping rate.


You won’t get tool advice, but if you know what you want it’s not a bad option.

I probably wouldn’t use carbide end mills on the Rong-Fu. That machine isn’t particularly rigid, and that will lead to a lot of carbide breakage. Manual milling in general often isn’t very friendly to carbide. You might be able to get away with it when using the power feed, but it probably won’t last long hand feeding. You’ll get less breakage climb milling, but that machine isn’t cut out to climb mill at even a moderate depth of cut.

If you ever move to the Tormach, Lakeshore Carbide is a great supplier for carbide end mills. I particularly like their variable flute offerings. The variable flute helps prevent chatter by reducing harmonic vibration caused by equally spaced flutes. That’s especially helpful on the Tormach which is again not very rigid for a CNC.


Replying to an old thread, BUT -

Any recommendations for a brick-and-mortar more central in Austin that I can pick up end mills from?

I see recs above for SparkTech in RR and Dixie Tool rib down south, both of which are a 20min drive from my neck of the woods in NW Austin before traffic.

I see there’s a Grainger on Research that I’ll stop by today but would love any advice y’all have!

As an aside, I’m specifically looking for a 1/16" end mill to cut a couple open slots down a ~2’ square bar of 8mm or 3/16" 6061 Al or mild steel (depending on what I can get my hands on most quickly).

You can email or call Sparktech for recommendations. They also have an ebay store called Drillman1. They will ship.

Drillman1 (Oliver Tool Company) on ebay located in Georgetown ships fast. I have also gone up there for free local pickup. He seemed really cool although I didn’t have too many questions for him.

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Spaktec is your nearest and best bet like everyone is saying. There’s not other real brick/morter store that has end mills for machining.

And they have a great selection to boot. Nice guys over there.

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Appreciate all the advice! I ended up making the run up to SparkTech. They were great and had what I needed and was able to stop by the metal shop while I was up there.

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